System and method for wastewater treatment

ABSTRACT

The present disclosure is directed towards systems and methods for the treatment of wastewater. A system in accordance with one particular embodiment may include a front end system including at least one resin tank configured to contain an ion exchange resin configured to target a particular metal. The at least one resin tank may be configured to receive an output from an oxidation reactor configured to receive a flow of wastewater from a wastewater producing process. The system may further include a central processing system configured to receive a saturated resin tank from the at least one resin tank. The central processing system may further include a vacuum filter band system configured to receive a slurry from the saturated resin tank and to provide a cascading resin rinse to the slurry. The central processing system may further include a repetitive stripping system configured to receive a metal-filled purification unit from a metal specific purification system. The repetitive stripping system may be further configured to sequentially apply the contents of a plurality of acid tanks to the metal-filled purification unit to generate a metal salt. Numerous other embodiments are also within the scope of the present disclosure.

RELATED APPLICATIONS

This application claims the priority of the following application, whichis herein incorporated by reference: U.S. Provisional Application No.61/119,567; filed 3 Dec. 2008, entitled: “Ion Exchange Based MetalBearing Wastewater Treatment and Recycling System Therefore”.

TECHNICAL FIELD

This disclosure generally relates to the field of industrial wastewatertreatment of metal bearing wastes. More specifically, the presentdisclosure relates to the equipment, operating procedures, chemicalprocesses, and physical processes employed to remove regulated and nonregulated contaminants from industrial wastewater.

BACKGROUND

Many industrial manufacturing processes generate wastewater containingmetals and other contaminants; both organic and non-organic. Due totheir inherent toxicity, regulatory authorities place strict limits onthe maximum concentration of certain metals that can be legallydischarged into the environment. In order to comply with theseregulations, factories employ wastewater treatment processes to removeregulated substances from the wastewater. The two principal wastewatertreatment methods are chemical precipitation and ion exchange.

Chemical precipitation is the most commonly used method today to removedissolved (ionic) metals from wastewater. Chemical precipitationtypically requires process operations of neutralization, precipitation,coagulation, flocculation, sedimentation, settling/filtration, anddewatering. It uses a series of tanks in which coagulants, precipitantsand other chemicals such as polymers, ferrous sulfate, sodium hydroxide,lime, and poly aluminum chloride are added to convert metals into aninsoluble form. In conjunction with adjusting the pH of the wastewater,this causes the metals to precipitate out of the water. Using aclarifying tank, the precipitates are allowed to settle, and then arecollected as sludge; filtration can also be used to remove the solids.Excess water in the sludge is removed using filter presses and/ordryers. The sludge, which itself is a regulated hazardous waste, is thensent offsite where it is stabilized by mixing with cement or polymers,and then buried in a hazardous material landfill. In this fashion theconcentrations of the regulated metals in the wastewater are reduced toa level in compliance with regulatory limits, allowing the water to bedischarged from the facility. However, the need to handle, transport,and dispose of the resulting hazardous sludges is one of the mostcostly, labor intensive, resource demanding and difficult problems withchemical precipitation as a wastewater treatment.

The inherent disadvantage of chemical precipitation is that it is anactive and additive process and, as such, requires that chemicals beadded to the wastewater in order to remove regulated metals. The sideeffect of this is an increase in the concentrations of many othersubstances, as well as a deterioration in characteristics such aschemical oxygen demand (COD) and conductivity; thus requiring additionaltreatments and rendering the water unsuitable or uneconomical forrecycling and reuse. Furthermore, the metals removed are not onlyunrecoverable, they are rendered into a regulated hazardous materialrequiring specialized disposal. As an additive process, chemicalprecipitation also increases, by orders of magnitude, the mass of wastematerial which needs to be handled, transported and landfilled.

As an active process, the effectiveness of chemical precipitation ispredicated on the proper operational procedures and dosing of chemicalsrelative to fluctuating variables such as the number of metals insolution and their concentrations, as well as the presence andconcentration of other substances. Underdosing of chemicals results inincomplete precipitation and removal of regulated metals, whileoverdosing wastes chemicals, generates additional volumes of sludge, andincreases cost. Currently, due to the consequences of illegaldischarges, most wastewater treatment operations simply absorb theadditional cost and overdose the chemicals in their treatmentoperations. Also, as each metal optimally precipitates at a differentpH, in wastewaters containing several metals, adjusting pH toprecipitate one metal may actually cause another metal to resolubilizeinto the wastewater. Lastly, chemical precipitation processes require alarge amount of floor space and capital equipment.

In contrast, ion exchange is a stoichiometrical, reversible,electrostatic chemical reaction in which an ion in solution is exchangedfor a similarly charged ion in a complex. These complexes are typicallychemically bound to a solid, insoluble, organic polymer substratecreating a resin; the most common of which is crosslinked polystyrene.Also, inorganic substrates like silica gel in various porosities andchemical modifications can be employed. Polystyrene crosslinking isachieved by adding divinyl benzene to the styrene which increasesstability, but does slightly reduce exchange capacity. With a macroporous structure, these ion exchange resins are normally produced in theform of small (1 mm) beads, thus providing a very high and accessiblesurface area for the binding of the functional group complexes; the sitewhere the ion exchange reaction actually occurs. The exchange capacityof the resin is defined by the total number of exchange sites, or morespecifically, of its total available functional groups.

In the actual ion exchange reaction, an ion such as sodium (Na+) looselyattached to a functional group of the complex is exchanged for an ion insolution such as copper (Cu2+); that is, the sodium ions detach from thecomplex and go into solution while the copper ion comes out of solutionand takes the place of the sodium ions on the complex. There are twotypes of ion exchange resins, cation exchangers, which exchange theirpositively charged ions (H+, Na+ etc.) for similarly charged ions (Cu2+,Ni2+, etc.) in solution, and anion exchangers, which exchange theirnegatively charged ions (OH−) for similarly charged ions in solution(chlorides, sulfates, etc.)

Ion exchange resins can also be selective or nonselective, based on theconfiguration and chemical structure of their functional groups. Nonselective resins exhibit very similar affinities for all similarlycharged ions, and consequently will attract and exchange all specieswithout significant preference. Selective resins have specializedfunctional groups which exhibit different affinities to different ionsof similar charge, causing them to attract and exchange ions withspecies in a well defined order of preference. The ion that isoriginally attached to the resin (e.g., H+, Na+, OH−) is of the lowestaffinity, which is why it will exchange places with any other ion theresin encounters. Generally speaking, the relative affinity a resinexhibits for a particular ion is directly correlated to the exchangeefficiency and capacity for that ion. However, as selective resins arebased on relative affinities, the actual selectivity is also relativeand not absolute.

Ion exchange resins can be regenerated once their capacity to exchangeions has been exhausted; that is, all of the functional groups havealready exchanged their original ion for one which was in the solution.This is also known as a resin which has been “saturated” in that itcannot adsorb any additional ions. The process of regeneration is simplythe reverse reaction of the original ion exchange. Clean water is firstflushed through the saturated resin to remove any particles, solids, orother contaminations. A solution containing a high concentration of theoriginal ion (e.g., the H+ ions contained in an acid) is then passedthrough the resin, causing the ion captured on the functional group(e.g., Cu2+) to forcibly detach from the functional group and solubilizeinto the solution and be replaced by the H+ ions from the acid.Depending on the type of resin (cation or anion, weak or strong)different chemicals are used to regenerate resins. In the case ofselective or chelating resins, the strong affinities exhibited by theseresins require greatly increased chemical consumption for theregeneration process. Regeneration results in a return of the resin toits original form (suitable for reuse) and a solution, also known as theregenerant, containing all of the metals or other ions stripped from theresin. Depending on its composition and complexity, some regenerants canbe further processed by methods such as electrowinning to recovermetals. The chemical consumption for regeneration as well as thedifficulty and costs of treating or disposing of regenerants containingmetals is the principal reason why ion exchange is often not a costeffective wastewater treatment option for metal bearing wastes.

SUMMARY OF DISCLOSURE

In a first implementation of this disclosure, a system in accordancewith one particular embodiment may include a front end system includingat least one resin tank configured to contain an ion exchange resinconfigured to target a particular metal. The at least one resin tank maybe configured to receive an output from an oxidation reactor configuredto receive a flow of wastewater from a wastewater producing process. Thesystem may further include a central processing system configured toreceive a saturated resin tank from the at least one resin tank. Thecentral processing system may further include a vacuum filter bandsystem configured to receive a slurry from the saturated resin tank andto provide a cascading resin rinse to the slurry. The central processingsystem may further include a repetitive stripping system configured toreceive a metal-filled purification unit from a metal specificpurification system. The repetitive stripping system may be furtherconfigured to sequentially apply the contents of a plurality of acidtanks to the metal-filled purification unit to generate a metal salt.

One or more of the following features may be included. The at least oneresin tank may include a plurality of resin tanks arranged in a seriesconfiguration. The ion exchange resin may be an iminodiacetic resin. Theiminodiacetic resin may be in a proton form.

In some embodiments, the metal specific purification system may beconfigured to receive a metal solution from the vacuum filter bandsystem. The metal specific purification system may include a pluralityof purification units. The metal-filled purification unit may begenerated by allowing the metal solution to flow through the pluralityof purification units. Each of the plurality of acid tanks may include adifferent acid concentration.

In some embodiments, the vacuum filter band system may include aplurality of spraying zones, each of the plurality of spraying zonesconfigured to apply a solution to the slurry and to substantiallydewater the slurry by applying a negative pressure to the vacuum filterband. The oxidation reactor may further include a reaction coilconfigured to pressurize at least a portion of the oxidation reactor.

In some embodiments, the at least one resin tank may include one or moreradio frequency identification (RFID) tags configured to record at leastone characteristic associated with the at least one resin tank. Themetal salt may be transferred to a metal salt processing system forcooling and crystallization.

In another implementation of this disclosure, a method in accordancewith one particular embodiment may include providing a front end systemincluding at least one resin tank having an ion exchange resinconfigured to target a particular metal. The method may further includereceiving, at the at least one resin tank, an output from an oxidationreactor configured to receive a flow of wastewater from a wastewaterproducing process. The method may additionally include receiving, at acentral processing system, a saturated resin tank from the at least oneresin tank and receiving a slurry from the saturated resin tank at avacuum filter band system. The method may also include providing acascading resin rinse to the slurry at the vacuum filter band system andreceiving, at a repetitive stripping system, a metal-filled purificationunit from a metal specific purification system. The method may furtherinclude sequentially applying, at the repetitive stripping system, thecontents of a plurality of acid tanks to the metal-filled purificationunit to generate a metal salt.

One or more of the following features may be included. The at least oneresin tank may include a plurality of resin tanks arranged in a seriesconfiguration. The ion exchange resin may be an iminodiacetic resin andmay be in a proton form.

In some embodiments, the method may further include receiving a metalsolution from the vacuum filter band system at the metal specificpurification system, the metal specific purification system having aplurality of purification units, and generating the metal-filledpurification unit by allowing the metal solution to flow through theplurality of purification units. Each of the plurality of acid tanks mayinclude a different acid concentration. The method may also includeproviding a plurality of spraying zones at the vacuum filter bandsystem, each of the plurality of spraying zones configured to apply asolution to the slurry and to substantially dewater the slurry byapplying a negative pressure to the vacuum filter band. The method mayadditionally include providing a reaction coil within the oxidationreactor configured to pressurize at least a portion of the oxidationreactor. The method may further include recording at least onecharacteristic associated with the at least one resin tank via one ormore radio frequency identification (RFID) tags. The method may alsoinclude cooling the metal salt at a metal salt processing system.

The details of one or more embodiments are set forth in the accompanyingdrawings and the description below. Features and advantages will becomeapparent from the description, the drawings, and the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exemplary embodiment of a wastewater system in accordancewith the present disclosure;

FIG. 2 is an exemplary embodiment of a wastewater system in accordancewith the present disclosure;

FIG. 3 is an exemplary embodiment of a wastewater system in accordancewith the present disclosure;

FIG. 4 is an exemplary embodiment of a wastewater system in accordancewith the present disclosure;

FIG. 5 is an exemplary embodiment of a wastewater system in accordancewith the present disclosure;

FIG. 6 is an exemplary embodiment of a wastewater system in accordancewith the present disclosure;

FIG. 7 is an exemplary embodiment of a wastewater system in accordancewith the present disclosure;

FIG. 8 is an exemplary embodiment of a wastewater system in accordancewith the present disclosure;

FIG. 9 is an exemplary embodiment of a wastewater system in accordancewith the present disclosure;

FIG. 10 is an exemplary embodiment of a wastewater system in accordancewith the present disclosure;

FIG. 11 is an exemplary embodiment of a wastewater system in accordancewith the present disclosure;

FIG. 12 is an exemplary embodiment of a wastewater system in accordancewith the present disclosure;

FIG. 13 is an exemplary embodiment of a wastewater system in accordancewith the present disclosure;

FIG. 14 is an exemplary embodiment of a wastewater system in accordancewith the present disclosure; and

FIG. 15 is an exemplary embodiment of a wastewater system in accordancewith the present disclosure;

Like reference symbols in the various drawings may indicate likeelements.

DETAILED DESCRIPTION

The present disclosure is directed towards an automated, modular, ionexchange resin based system that may process metal bearing wastewaterssuch that the treated water can be recycled, or discharged in compliancewith regulatory standards. Embodiments of the present disclosure maycapture the metals within the wastewater and then separate, purify andconcentrate each individual metal into commercially salable end productssuch as metal sulfates.

The system may be comprised of a front end unit situated at the site ofwastewater generation, and a central processing facility where the metalbearing ion exchange columns from numerous front end units are collectedand processed. Alternatively, where treatment volumes, economic, and/orregulatory considerations so merit, the central processing facility canbe located together with the front end system.

Embodiments of the present disclosure may be used to collectenvironmentally regulated metals from the rinse water streams of platingbaths and similar operations. Rinse water may be generated when variouswork pieces are cleaned to receive the final, surface washed, product.Excess plating fluid may need to be removed prior to drying, packing andshipping of the work pieces. The rinse water quality or the abundance ofmetals which are carried into the rinse water may be dependent upon therinse process itself (e.g., spraying, dipping, stifling, etc.) and alsothe overall surface properties and nature of the plated work piece.Thus, the concentration of toxic metals such as copper, nickel, zinc andchrome may vary at a particular shop.

Generally, the present disclosure may be used to provide safe andefficient removal of environmentally regulated metal contaminationson-site at various plating facilities. Embodiments of the presentdisclosure may include replacement of exhausted resin tanks withre-conditioned, full capacity tanks and transport between the platingfacility and an off-site central processing facility. Embodiments of thepresent disclosure may be used to recover industrially valuable metalsincluding, but not limited to, Cu, Zn, Ni and Cr as metal salt productsin liquid or solid form. Once these metals have been successfullyrecovered, they may be re-distributed as high quality, recycled metalsalts back to the plating industry or other consumers. The systems andmethods described herein may be used to provide safe and efficienttreatment of residual toxic metals and reduction of the overall wastevolume by more than 80%.

In some embodiments, the present disclosure may apply to a wide varietyof processes where metals from a surface treatment are carried intorinsing waters and waste streams. The teachings of the presentdisclosure may be used to replace, in whole or in part, conventionalsludging and landfill technology, which has been employed since theearly days of wastewater treatment. While the present disclosure maydiscuss industrial metals such as copper, nickel, zinc and chromium, itis by no means intended to be limited to these metals, as the teachingsof the present disclosure may be used to treat any numerous types ofmetals.

Ion exchange technology is based upon the electro static interaction ofions dissolved in water with certain organic functional groups. Thesegroups may attract the positively or negatively charged ions andexchange their proton or hydroxide ion used to pre-condition thefunctional groups. Positively charged ions are referred to as cationswhile the negatively charged ions are referred to as anions. The organicfunctional groups may include, but are not limited to, sulfonic acid,carboxylic acids, tertiary amines, and quaternary amines. The organicgroups are typically bound chemically to styrene or acrylic copolymers.The polymers may provide a water insoluble backbone with a high surfacearea to filter the ions form a water stream pumped in an efficient andcontrolled manner.

In some embodiments of the present disclosure, the ion exchange polymersor resins may be filled, for example, into tanks or columns (e.g.,80-100 L). This may allow for the easy replacement of a saturated ionexchange resin. A saturated ion exchange resin is a polymer where all,or the vast majority of, available functional groups have been replacedwith the target ions. The resin at this point may require reconditioningwhich may allow for the harvesting of the “loaded” ions.

In some embodiments, ion exchangers or resin tanks may be immobilizedand may act like an ion selective filter. This means that much dilutedmetal ions in water streams are adsorbed and concentrated on the ionexchange resin. Very large volumes of water can be treated with relativesmall ion exchange tanks or cartridges. The other contaminants in thewater stream are not attracted to the ion exchange resins. Wastewatertreatment is therefore very effective and feasible when employing ionexchange technology. Also, there are ion exchange resins which supportan even more selective organic functional group. These ion exchangeresins may allow for an additional level of selectivity and adsorptioncapabilities.

Embodiments of the present disclosure may utilize both non-selective andmetal selective ion exchange resins. One of the strengths in employingthe selective ion exchange resins is the capability to attract specificmetal ions stronger than other metals. For example, copper is attractedalmost selectively to ion exchange resins of the imminodiacetic acidtype. The transition metals (i.e. Cu, Zn, Ni) form a well-definedhierarchy of attraction to this organic functional group.

In contrast, a non-selective exchange resin may be able to adsorb a widerange of ions and therefore remove potential contaminations completely.In some embodiments of the present disclosure these resins may be usedfor water demineralization prior to recycle or as polishers.

Referring now to FIG. 1, a schematic 100 depicting an embodiment of awastewater process in accordance with the present disclosure isprovided. In some embodiments, the wastewater process may include both afront end system 102, which may take place at a customer site such as aplating facility, and a core process 104, which may occur at a centralfacility.

In some embodiments, front end system 102 may consist of severalindividual processes assembled linearly into a seamless treatmentsystem, which may be controlled by a programmable logic controllerlinked to sensors, pumps, valves, and other hardware associated withsystem 102. Each process may remove or treat a particular contaminant inthe wastewater either to meet, or exceed, regulatory discharge criteriaand/or to ensure proper operation of the ion exchange tanks for metalremoval. Non-regulated substances may be disposed of on site, whileregulated materials (primarily transition metals) may be collected incolumns and cartridges for transport to a central processing facility.

In some embodiments, front end system 102 may be configured to perform apassive removal of the metal contamination in the rinse waters generatedat the plating facility. The effluent out of front end system 102 may befiltered to contain little or no regulated or toxic metals and mayeither be discharged and/or treated for its organic contamination (e.g.,chemical oxygen demand (COD) or total organic carbon (TOC) removal).

Once the loading capacity of the ion exchange resins in front end system102 is reached, the ion exchange resin tanks may be exchanged withfreshly reconditioned resin tanks. The exhausted and metal loaded tanksmay be transported back to core process 104 at the central processingfacility. The central facility may harvest the target metals from theloaded resins and re-conditions the material for re-use at the platingsites.

In some embodiments, the harvested metals may be collected as a liquidhaving a mixed metals concentrate. This solution may then be used toisolate and purify the individual target metals, copper, nickel andzinc. The metals may be collected as a very highly concentrated metalsulfate solution.

In some embodiments, the product of core process 104 may be provided toproduction phase 106, which may be configured to create acrystallization of the metal liquors to generate metal sulfate salts.The sulfates may be fed back into into the market as resource forplating facilities 102 or to related industries.

In some embodiments, some or all of the metals that are not economicallyviable or are too toxic to be discharged untreated, may undergo aconventional hydroxide precipitation. The sludges received may betreated and disposed of via the existing waste management facilities andcompanies. The sludge volume produced by core process 104 at the centralfacility may be a tiny fraction of the originally produced amountgenerated using existing technologies. Core process 104 and productionphase 106 may also allow for improved detoxification to provide a safeand reliable service to the public and environment.

Front End System

Referring now to FIG. 2, one exemplary embodiment of front end system200 is provided. System 200 may include one or more resin tanks 202A-D,which may be configured to contain an ion exchange resin. Numerous ionexchange resins may be used in accordance with the present disclosure.For example, some ion exchange resins may be strongly acidic, stronglybasic, weakly acidic, or weakly basic. The ion exchange resin may alsobe a chelating resin, such as chelex 100, or any other suitable ionexchange resin. The adsorption of ions or metal complexes is howeveralso possible with inorganic support materials like silica gels orchemically modified silica gels. The adsorption mechanism may be ofhydrophobic interaction or hydrophilic interaction mechanism or othernature.

In some embodiments, the efficiency of the filtering and metal removalmay be significantly improved by employing a pre-selective ion exchangeresin of the iminodiacetic acid type as shown in further detail in FIG.9. In this way, precious ion exchange capacity may not be used up by themetal ions which are in high natural abundance but are not regulated bythe authorities because of their non-toxic character (e.g., sodium,calcium, magnesium, potassium, etc.). This way the first economicpre-selective mechanism may be applied to preserve resources and ionexchange capacity. Thus, embodiments of the present disclosure may beused to remove transition metals such as copper, nickel, and zinc with apreference over the monovalent base metals (Na, K, etc.) or the divalentbase metals (e.g., Ca and Mg). This pre-selection may allow forenriching only the metals which are valuable target metals and/or thosethat are regulated by the environmental authorities.

In some embodiments, system 200 may further include a control panel 204,which may be configured to control one or more operations of system 200.Control panel 204 may include a programmable logic controller (PLC) 205,or similar device, which may be configured to monitor and/or govern theoperating parameters of front end system 200. Sensors may be placedthroughout system 200 to provide operational system data including, butnot limited to, the volume in various tanks, system throughput, flowrates, pH of the wastewater in each process step, volume of availablechemical reagents, oxidation/reduction potential, pressure, etc. PLC 205may be configured to process this incoming data on a real time basis andthen issue commands to pumps, valves, and other system hardwareaccording to the algorithms of its proprietary software. A flowmeter, orsimilar device, may measure the total throughput volume of the system,while several smaller flowmeters may monitor the flow rate throughindividual components of system 200. In some embodiments, PLC 205 may beoperatively connected to a communications system whereby data may betransmitted wirelessly or via the internet to a centralized controlcenter. This may allow for remote monitoring of the operations of system200. This may also provide for decreased personnel costs as well as foroptimizing the scheduling of resin tank changes and/or replacement.

In some embodiments, control panel 204 and/or PLC 205 may allow anoperator to control the flow of influent wastewater using influent pump206. Influent pump 206 may be configured to provide influent wastewaterto one or more storage tanks within system 200, e.g., oxidation tank208. Oxidation tank 208, which will be described in further detailhereinbelow, may provide an output to relay tank 210. Relay tank 210 maybe operatively connected to cartridge filter 212 and activated carbon(AC) filter 214. One or more filter pumps 216 may also be used to pumpthe wastewater through various portions of system 200. System 200 mayalso include acid tanks such as hydrochloric acid (HCL) tank 218 andsodium hypochlorite (NaOCL) tank 220, which may be operatively connectedvia pumps, valves, etc to portions of system 200. Additional details ofsystem 200 are described below with reference to FIG. 3. Depending onthe components recovered and the adsorption mechanism used, otherchemicals might be used.

Referring now to FIG. 3, an exemplary embodiment of system 300 showingresin tanks 302A-G arranged in a series arrangement is provided.Initially, wastewater from the customer may be stored in buffer tank301, which may be configured to regulate the flow of wastewater intosystem 300. In addition, the concentrations of the varying contaminantsmay be modulated and normalized (if required). Buffer tank 301 may alsoallow for the assaying of wastewater characteristics including, but notlimited to, metals present and their respective concentrations, pH,suspended solids, chemical oxygen demand, and oxidation/reductionpotential.

In some embodiments, the initial resin columns (e.g., 302A and 302B) maybecome saturated first. This design may allow for a partially orentirely mobile system, which may provide for easy transfer of the resintanks to and from the central facility. Resin tanks 302A-G may be of anysuitable size, for example, in one particular embodiment each of tanks302A-G may be configured to contain approximately 80-100 liters of ionexchange resin. Each resin tank associated with tanks 302A-G may furtherinclude one or more RFID tracking tags or similar devices, which may beconfigured to provide monitoring capabilities, which are discussed infurther detail below.

In some embodiments, each resin tank may be configured to continuouslyextract copper (Cu), zinc (Zn), and Nickel (Ni) from the rinse watergenerated by the plating process. This may be achieved by pumping therinse water over the ion exchange resin tanks 302A-G after intermediatestorage in relay tank 310. The actual trapping of the transition metalsCu, Ni, and Zn may occur in a passive way. One or more pumps may supplythe energy required for the loading or filtering process. After therinse water has passed through resin tanks 302A-G, metals such ascopper, nickel, and zinc, for example, may be removed to a level belowthe local discharge limits (e.g., 1-3 mg/L, depending on the metal). Thewater may then either be treated further for its organic contaminationor, if complying already with the local regulation, may be dischargedinto the municipal drains. As the loading capacity of the ion exchangeresin is known (i.e., volume of resin), the filter capacity may beeasily adjusted to the observed levels of metal contamination (e.g.,individually for each workshop). For example, a standard usage timeuntil replacement with a fresh set of resin tanks may occur afterapproximately ten working days (e.g., 2 operational weeks utilizing 40m³ of rinse water daily).

In some embodiments, each of resin tanks 302A-G may be wholly orpartially enclosed and may be fitted with appropriate inlet and outletopenings for the flow of the water to be treated. Resin tanks 302A-G maybe configured to contain and support the resin, thus creating a resinbed of defined height and depth. This configuration may also provide theenvironment for the ion exchange reaction to occur as the wastewater maybe passed through each of resin tanks 302A-G and evenly distributedthroughout the resin bed. There are several possible flow designs thatmay be used in order to pass solutions through each of resin tanks302A-G, including, but not limited to, top in/bottom out, bottom in/topout, and top in/top out. Resin tanks 302A-G may be connected toadditional equipment, such as pumps, valves, piping, etc., which mayregulate the inflow/outflow of wastewater, reagents for regeneration,and backwash solutions. As ion exchange resins may undergo fouling andcongestion from organics and solids, only certain types of wastewatersmay be suitable for ion exchange treatment. In other cases where thelevels of inappropriate contaminants are within a manageable range,pretreatment steps such as filtering and oxidation may be taken prior tothe wastewater entering resin tanks 302A-G in order to ensure properoperation.

In operation, during the loading phase, one or more of resin tanks302A-G may contain fresh resin and wastewater may be pumped through theresin tanks at a rate designed to provide an adequate amount of contacttime between the wastewater and the resin for the ion exchange reactionto occur. As wastewater flows through the resin bed, the ion exchangereaction may occur and metals and other ionic contaminants may beremoved from the wastewater and trapped on the resin. As the exchangecapacity of the resin becomes progressively exhausted, some metals maynot be captured by the resin and may begin to leak out of, or“breakthrough”, one or more of resin tanks 302A-G. Consequently, resintanks 302A-G may be configured in series, as shown in FIG. 3, so thateach resin tank may be able to capture any metals or ions which escapethe tank preceding it; thus ensuring a successful treatment of thewastewater. Once a resin tank becomes saturated, it may be taken offline(e.g., using control panel 204), or out of the series of tanks 302A-G inservice operation, and regenerated. The physical handling and exposureto chemicals may cause degradation of the resin's structure and exchangecapacity over time. Therefore, this loading/regeneration cycle may beperformed repeatedly until the operational life of the resin is reached,and it is no longer economical or possible to continue use of the resin.At that point, the exhausted resin may be discarded, and resin tanks302A-G may be filled with new resin.

System 300 may further include a control panel such as control panel 204shown in FIG. 2, which may be configured to control the operation ofvarious components throughout the system. Control panel 204 may includea programmable logic controller or similar device, which may beoperatively connected to the valves, pumps, sensors and control lines ofsystem 300. Control panel 204 may include numerous types of circuitry,which may be in communication with the components of system 300.

As used in any embodiment described herein, the term “circuitry” maycomprise, for example, singly or in any combination, hardwiredcircuitry, programmable circuitry, state machine circuitry, and/orfirmware that stores instructions executed by programmable circuitry. Itshould be understood at the outset that any of the operations and/oroperative components described in any embodiment or embodiment hereinmay be implemented in software, firmware, hardwired circuitry and/or anycombination thereof.

As discussed above, front end system 300 may use a pre-selective ionexchange mechanism to pre-separate many regulated metals from thenon-toxic base metals. Sensors may be placed throughout system 300 tomonitor operational parameters and feed data to programmable logiccontroller 205 associated with control panel 204. Each process withinsystem 300 may remove or treat a particular wastewater contaminant toparticular concentrations, which at a minimum, satisfy recycling orregulatory discharge standards.

In some embodiments, relay tanks, such as relay tank 310, may regulateinput flow rate and allow for the assaying of the wastewater as well aspH adjustment (as required). Relay tank 310 may be configured to receivean output from numerous sources, such as oxidation tank 308. Oxidationtank 308 may be configured to destroy and/or reduce organic agents thatcould potentially negatively impact the efficiency of the ion exchangeresin tanks 302A-G that follow. The output from relay tank 310 may besent to one or more filters, including, but not limited to cartridgefilter 312 and activated carbon filter 314.

In some embodiments, cartridge filter 312 or other mechanical filterssuch as a mesh bag or sand filter, may remove suspended solids and otherparticles. Cartridge filter 312 may provide an output to activatedcarbon filter for additional filtering operations. For example,activated carbon filter 314 may polish the wastewater to remove anypotentially remaining interfering organics and/or suspended solids.

Once the filtering is complete, the wastewater may be sent to resintanks 302A-G, which may contain various types of ion exchange resins.Resin tanks 302A-G may be housed in mobile tanks, which may be taken offor put on line as necessary. Resin tanks 302A-G may be configured tocapture target metals as well as other cationic or anionic species.Individual resin tanks 302A-G may be radio frequency identification(RFID) tagged and linked with a central database mining and logisticalsoftware system.

In some embodiments, system 300 may further include one or more acidtanks, which may be configured to provide an acid solution to portionsof system 300. For example, H₂SO4 acid tank 318 and NaOCL acid tank 320may be connected to one or more lines or tanks of system 300. Theseparticular acids are merely provided for exemplary purposes as variousother types of acids and solutions may be used as well.

Referring now to FIG. 4, an additional embodiment of front end system400 is depicted. System 400 may include buffer tank 401, which may beconfigured to store wastewater in order to regulate the flow rate intosystem 400. In addition, the concentrations of the varying contaminantsmay be modulated and normalized (if required). Buffer tank 401 may alsoallow for the assaying of wastewater characteristics including, but notlimited to, metals present and their respective concentrations, pH,suspended solids, chemical oxygen demand, and oxidation/reductionpotential.

In some embodiments, wastewater may be pumped at a designated flow ratefrom buffer tank 401 to inline oxidation reactor 408. Oxidation reactor408 may be configured to destroy interfering organic agents such ascyanide and surfactants and is discussed in further detail withreference to FIGS. 5-6. Oxidation reactor 408 may receive NaOCL fromacid tank 420 and HCL from acid tank 418. Using oxidation chemicals suchas sodium hypochlorite, hydrogen peroxide, sodium hydroxide, orelectrochemical techniques, wastewater may be oxidized at low (e.g.,4-6) pH to prevent and/or reduce precipitation of target metals, andunder positive pressure to keep the active oxidation agent in solution.The dual chamber design of oxidation reactor 408 may create a two stepoxidation of organic, as well as inorganic interfering contaminants.Oxidation reactor may include one or more outlet ports, which may beconfigured to allow various gases to travel to scrubber 427 and/ordegassing chamber 428.

In some embodiments, the wastewater may be pumped from oxidation reactor408 to mechanical filter 412. Mechanical filter 412 may be any suitablefilter including, but not limited to, sand filters, bag filters, etc.Mechanical filter 412 may be configured to remove suspended solids andother particles to prevent clogging or fouling of ion exchange (i.e.,resin) tanks 402 downstream in system 400.

In some embodiments, the wastewater may exit mechanical filter 412 andbe pumped through activated carbon filter 414. Activated carbon filter414 may be configured to adsorb any interfering organics that may stillremain dissolved, as well as any residual suspended solids. At thispoint, the wastewater may be substantially free of any solids,particles, interfering organics, chelating agents, or other contaminantsthat could adversely impact the efficiency of the ion exchange processto follow.

In some embodiments, upon leaving activated carbon filter 414, the pH ofthe wastewater may now be adjusted and controlled (if necessary,depending upon the metals present) in a relay tank such as relay tank310 depicted in FIG. 3. The wastewater may then be pumped at adesignated flow rate into ion exchange tanks 402A-B, which may be placedin series and may contain selective ion exchange resins. While only twopre-selective ion exchange tanks are depicted in FIG. 4, it isenvisioned that any number of ion exchange tanks may be used withoutdeparting from the scope of the present disclosure. Softening, basecation and anion demineralization may occur in tank 402C.

In some embodiments, ion exchange tanks 402A-B may be constructed out ofan extreme pH (e.g., acid and alkaline) resistant, pressure bearing andunreactive material such as fiberglass reinforced plastic (FRP). Ionexchange tanks 402A-B may be of a suitable height and diameter to createthe proper resin bed depth for the flow rate of system 400. The tanksmay also need to be sized to allow for sufficient room for fluidizationand expansion of the resin bed. The number of ion exchange tanks usedmay be dependent on the desired daily volume capacity and time involvedbetween exchanging of tanks. Each ion exchange tank may be fitted with abypass valve, allowing for on-the-fly servicing of an individual tank,or tanks, without the need for a shut down of the entire front endsystem 400.

In some embodiments, each individual ion exchange tank may be mobile andset in a frame or housing, which may provide additional protection aswell as simplified handling and transportation. Each ion exchange tankmay also be fitted with a unique radio frequency identification (RFID)tag linked into a logistical management system. Handheld, truck mounted,and central processing facility mounted sensors may allow for the realtime tracking and management of all of the ion exchange tanks (e.g.,402A-B), as well as for the creation of an operational history, whichmay be managed by database software. In this manner, the history of eachion exchange tank, including parameters such as, but not limited to,service location, service time, metals captured, exchangeefficiency/capacity, regeneration results, and operational life can beaccumulated in the database. System 400 may further include databasemining software, which may be used to analyze the data to identifyoperational trends and efficiencies; which may then be used to optimizeoperating procedures and lower costs.

In some embodiments, for example where large volumes of wastewater mustbe treated, several sets or strings of ion exchange tanks may be placedin parallel. Each individual set or string may include an independentbypass valve. In this layout, an individual set of ion exchange tanksmay be taken offline for servicing while the other set(s) of tanks maycontinue in operation. This may allow for continuous operation of frontend system 400 with minimal downtime. Alternatively, larger ion exchangetanks may be mounted directly on a mobile platform such as a flatbedtrailers to process high volume applications.

In some embodiments, each set of ion exchange tanks (e.g., 402A-B) mayinclude a sensor positioned between two ion exchange tanks near the endof the series, which may be designed to detect the presence of metals inthe wastewater. A positive signal from this sensor may indicate amalfunction or breakthrough from the ion exchange tank preceding thesensor. This sensor may trigger an alarm that signals the operator thatan exchange of ion exchange tanks may be necessary. Further, a visualindicator consisting of a clear segment of piping containing ionexchange resin may be located next to the sensor and also between thetwo ion exchange tanks. Typically, the ion exchange resin may changecolor as they adsorb metals. Consequently, a change in the color of theindicator resin may allow for a visual backup alarm to the operator thatbreakthrough has occurred and that an exchange of ion exchange tanks isrequired. This change in color may be determined using additionalsensing equipment or via visual inspection by the operator. This designmay insure that metal bearing wastewater does not escape system 400 as awhole, and that treated wastewater leaving system 400 is in compliancewith regulatory discharge limits and/or recycling water qualitystandards. Additional sensors and indicators may be placed throughoutthe series of ion exchange tanks in order to monitor operationalparameters.

In some embodiments, once the metals and other ionic species have beencaptured by ion exchange tanks 402A-B, the effluent from these tanks maybe stored in a tank 402C prior to being sent to polishers 422 and 424.Polishers 422 and 424 may be used to remove any remaining suspendedparticles that were not removed previously. Upon leaving polishers 422and 424, the wastewater may be sent to recycled water storage tank 426for subsequent storage. The resulting water in water storage tank 426,may be suitable for discharge from the facility, or alternatively, forrecycling and reuse onsite. Additional acid tanks 430 and 432 may beoperatively connected to recycled water storage tank 426 and configuredto provide various acids and/or solutions to tank 426 through one ormore transmission lines. In cases where recycling may require higherpurity water, the treated water may be pumped through a reverse osmosissystem or treated with a traditional demineralization system prior toreuse.

In some embodiments, once ion exchange tanks 402A-B have captured thenecessary metals and other contaminants ion exchange tanks 402A-B maythen be transported to the central processing facility for regenerationand recycling. A positive air pressure device may be used to purge eachtank of excess water in order to minimize weight and facilitate handlingand transportation. Some wastes that are free of regulated materials(i.e. metals), such as backwash from a sand filter, may be disposed ofonsite and may not require transportation. Alternatively, inapplications where economic, regulatory or other considerations merit,(such as large daily wastewater volumes or restrictions on the transportof regulated materials), the central processing facility may be locatedon the same site as front end system 400. This layout may eliminatehandling and transportation costs with no detrimental effect oncapabilities or effectiveness of the system.

Referring now to FIGS. 5-6, as discussed above, systems 300 and 400 mayinclude oxidation tank 308, 408, 500, which may be placed between theinfluent wastewater stream and resin tanks 302A-G. Occasionally, duringthe plating process, some metals may be plated while they are stabilizedwith a chemical agent, typically cyanide. However, cyanide is a strongchelating agent and may interfere with the ion exchange chemistry. Inthis way, cyanide may prevent the metal ion from being trapped oradsorbed by the functional groups within resin tanks 302A-G. Thus, theprocess could lose efficiency and toxic metals and cyanides could escapethe proper treatment. Cyanide may be destroyed with a strong oxidationagent such as sodium hypochlorite or bleach (NaOCl in NaOH solution, pHca. 12). The reaction may occur in a stirred reactor prior or parallelto the hydroxide precipitation.

In order to address this issue, in some embodiments, system 300 mayinclude oxidation reactor 500, which may be configured as a flow throughreactor to allow for the destruction of cyanide and other organiccontamination in the rinse water. Oxidation reactor 500 may includeoxidation vessel 502 having inlet port 504, air inlet port 506, outletport 508, exhaust port 510, and reaction coil 512. Oxidation reactor 500may be used to oxidize cyanide at a low pH (e.g., 4-6) while thereaction solution may be pressurized in reaction coil 512. The low pHmay prevent hydroxide precipitation of the valuable target metals whilethe pressure maintains the active chlorine in physical solution. In thisway, the reduced oxidation potential of the sodium hypochloride or otherstrong oxidation agents may be compensated and even improved.

In some embodiments, inlet port 504 may be configured to allow numerousliquids to enter oxidation vessel 502. For example, rinse water fromvarious plating operations may enter oxidation vessel 502 through inletport 504. Inlet port 504 may also allow for the addition of waterperoxide and various other agents such as bleach. Air inlet port 506 maybe configured to allow for the addition of air or other gases tooxidation vessel 502, which may result in the removal of chlorine gasthrough exhaust port 510. Outlet port 508 may be associated with acarbon filter or similar device, which may be configured to removechlorine and/or decomposed organics. Exhaust port 510 may act as aconduit to receive cyanide and chlorine gas for removal. A low pH mayresult in outgassing within oxidation vessel 502, however, a high pH mayresult in the formation of metal hydroxides, as such pressurizedreaction coil 512 may be used to counteract a high pH.

In some embodiments, reaction coil 512 may be arranged using piping in astacked coil in order to create an enclosed and elevated pressureenvironment while increasing the time the wastewater remains inoxidation vessel 502. Reaction coil 512 may be of any suitable length,in one embodiment, reaction coil 512 may be a couple of meters inlength. Dosing pumps may be operatively connected to oxidation vessel502 via piping in order to adjust pH and for the introduction of theoxidizing agent to the wastewater. Mixing may be achieved by theinclusion of a static mixer in the reactor following inlet port 504.Additionally or alternatively, mixing may also be conducted withtraditional stirring techniques prior to introduction into reaction coil512. The application of positive pressure in this first step may enrichvolatile oxidation agents in the liquid phase, and prevent them fromdegassing. This may increase oxidation efficiency while extending thecontact time of the oxidizing agent with the wastewater; even when in achemically unfavorable, slightly acidic pH environment.

In some embodiments, in an additional oxidation step, the wastewater mayexit reaction coil 512 and flow into a second chamber within oxidationreactor 500. The chamber may be sealed to prevent the escape of fumes orother oxidation by-products. Extensive aeration of the wastewater may beachieved with the introduction of air through air inlet port 504 intooxidation vessel 502 via a pump. Potentially cracked contaminants may befurther oxidized by the oxygen in the air while a scrubber system,operatively connected to oxidation vessel 502 via exhaust port 510, isused to control degassing and remove toxic fumes and/or volatileoxidation by-products. This step may also effectively strip out excessoxidant from the now oxidized wastewater, cleansing the wastewater andminimizing any fouling or other contamination of the ion exchange resinslater in the system.

In some embodiments, integrated with oxidation vessel 502 may be anexcess chlorine removal chamber. With the air stripping approach, excesschlorine may be removed from the now cyanide free rinse water solutionto avoid damage of the ion exchange resin. The chlorine may be safelytransferred through exhaust port 510 and trapped in a caustic scrubber.The saturated scrubbing solution may be potentially re-injected as anoxidation agent in oxidation tank 502.

In some embodiments, reaction coil 512 may be pressurized and mayfurther prevent early degassing of the reaction fluid. Reaction coil 512may allow extended reaction time at a pH below 8, which may assist inpreserving the target metals in solution while destroying cyanide andorganic additives.

Referring again to FIG. 6, an additional embodiment depicting oxidationreactor 600 is provided. Oxidation reactor 600 may further includeexcess chlorine removal chamber 614. In this embodiment, two discretetreatment chambers, namely oxidation vessel 602 and excess chlorineremoval chamber 614 are provided adjacent one another. Reaction coil 612is provided within oxidation vessel 602 affixed to inlet port 604, whichmay be configured to provide rinse water from the plating operationsand/or acid and hypochlorite. Oxidation vessel 602 may be configured toprovide an extended reaction with active chlorine at a pH ofapproximately 4-6.5. Excess chlorine chamber 614 may be configured toscrub excess chlorine from the treated solution using aeration orsimilar techniques. In some cases, the low pH may be necessary tomaintain the solubility of the target metal salts.

Referring now to FIG. 7, a flowchart 700 depicting operations associatedwith an oxidation reactor of the present disclosure is provided.Operations may include storing and/or receiving rinse water from theplating process at a buffer tank (702). Operations may further includeutilizing a positive pressure reaction coil and static mixer associatedwith the oxidation reactor (704). Here, an oxidation agent may be addedand a pH adjustment may occur. Degassing and aeration may be performed,e.g., using an air blower or other suitable techniques (706). Theeffluent may be received at the ion exchange tanks (708) and any exhaustfumes from the oxidation reactor may be sent to a scrubber fordetoxification (710). This is merely one exemplary set of operations asnumerous other operations are also within the scope of the presentdisclosure.

Referring now to FIG. 8, a flowchart 800 depicting operations associatedwith systems and methods of the present disclosure is provided.Operations may include receiving and subsequently storing rinse waterfrom plating baths (802). Operations may further include oxidationoperations such as those described above with reference to FIG. 7 (804).Operations may further include filtering (806), via an activated carbonfilter prior to providing wastewater to resin tanks (808). The remainingwater may undergo a pH adjustment (810) prior to undergoing reverseosmosis for water recovery/recycle (812) or additionally oralternatively, being recycled untreated for workpiece pre-treatment(814). Upon exiting the front end system, the treated water may be readyfor recycling onsite, or to be discharged in compliance with applicableregulatory discharge guidelines. While non-regulated substances may bedisposed of onsite, the metal bearing ion exchange tanks may be sent toa central processing facility for resin regeneration, as well asprocessing and recycling of the metals. This is merely another exemplaryset of operations as numerous other operations are also within the scopeof the present disclosure.

Central Processing

Central processing facility may serve as the collection and processingpoint for saturated or partly saturated ion exchange (resin) tanks fromthe front end system. At the central processing facility, the ionexchange tanks from the front end system may be regenerated for reuseand the metals may be recovered in a process consisting of multiplestages including, but not limited to, ion exchange tank stripping andresin regeneration, metals separation and purification, and finalprocessing of recovered metals into end products.

In some embodiments, the exhausted and loaded resin tanks, e.g., resintanks 302A-G, may arrive at the central processing facility and areunloaded. The resin may be removed from the tanks and acid treated in abatch process. The acid may remove the metals collected on the resinand, combined with the rinse water, provide the loading solution for theisolation and purification unit described below. The acid may alsoreturn the ion exchange resin into its proton form.

In some embodiments, it should be noted that iminodiacetic ion exchangeresins in their proton form may be used. This may minimize the use ofchemicals and rinsing water requirements. A savings of approximately 20%chemical costs and 50% of rinse water may be achieved using thisapproach. Use of the chelating ion exchange resin in a proton form mayassist in conserving tremendous amounts of caustic, brine and especiallyrinse water. Moreover, there is a significant benefit in preventing theresin from swelling while washing and regenerating with caustic (e.g.,high pH values of approximately 10-14). The swelling may occur as aresult of a volumetric expansion of the cross linked poly styrenebackbone. This swelling and the subsequent contraction at a low pH isone of the major reasons for resin attrition. Therefore, avoiding highpH values in which the resin is operating may increase the life time ofthe material.

In some embodiments, at the site where the front end system isinstalled, saturated ion exchange tanks, e.g., 302A-G, may be exchangedfor freshly reconditioned ion exchange tanks and then transported backto the central processing facility. Where economic, regulatory, or otherconsiderations so merit, the central processing facility may be locatedat the same site as the front end system, which may eliminate the needfor handling and transportation of the ion exchange tanks from the frontend system. Additionally and/or alternatively, the central processingfacility may also have a front end system installed such that theprocess waters used in the various stages may also be treated andrecycled into the process, further reducing costs and chemicalconsumption.

In some embodiments, and as discussed above with reference to FIG. 3,portions of the front end system may include RFID tracking. For example,upon arriving at the central processing facility, the ion exchange tanksmay be sorted and grouped based on data received from their respectiveRFID tags. The grouping may allow for the most efficient processing ofion exchange tanks, for example, tanks exhibiting similarcharacteristics. More specifically, regarding the metals they containand their relative concentrations. Database software may be configuredto analyze the operational histories of the incoming ion exchange tanks(based upon their RFID identifications) and suggest optimal processingparameters to the operators. This categorization and sorting process mayimprove the efficiency of the facility by leveling out the varying inputvariables from different front end collection sites. This, inconjunction with the pooling of recovered metals into homogeneous volumebatches reduces the range and number of variables of each batch,simplifying processing and reducing costs.

Referring now to FIG. 10, one exemplary embodiment of a conveyor beltvacuum filter band stripping and regeneration system 1000 is provided.System 1000 may be located at the central processing facility, which maybe located on or offsite from the front end system. System 1000 mayutilize a cascading arrangement, which may reuse lesser contaminatedrinsewater in a repetitive manner to help minimize overall rinsewaterconsumption and provide a high degree of control over the compositionand characteristics of the regenerant. This may also result in a moreefficient use of chemical inputs, thus lowering operational costs.

In some embodiments, system 1000 may be configured to receive one ormore saturated ion exchange tanks 1002 from the front end system. System1000 may perform a stripping and regeneration process in order torecover the captured metals and recondition the resins to their originalstate.

In some embodiments, a saturated ion exchange tank 1002 may be receivedat system 1000. The ion exchange resin may be removed from ion exchangetank 1002 and placed in resin holding vessel 1004. The resin may beextracted from each ion exchange tank 1002 using any suitable technique,for example, using high velocity water jets. This procedure mayeffectively rinse the resin to remove any trapped particulates orsolids, and also fluidize the resin to counteract any compaction of theresin beds which may have occurred during the loading stage of the frontend process.

In some embodiments, once the resin has been fluidized, resin slurrypump 1005 may be used to transfer the resin from holding vessel 1004 tovacuum filter band 1006. The operational parameters of slurry pump 1005may be controlled via a PLC associated with a control panel, which maybe similar to that shown in FIG. 2. It should be noted that some or allof the components of system 1000 may be controlled via a PLC similar tothat described above with reference to FIG. 2. The fluidized resin, in aslurry form, may then be spread onto vacuum filter band 1006.

In some embodiments, vacuum filter band 1006 may be constructed out ofany suitable material. For example, filter band 1006 may be a porousmaterial such as a mesh, which may be configured to receive a negativepressure or vacuum in order to dewaterize or partially dewaterize theresin on the band. Vacuum filter band 1006 may be located as part of acontrollable (e.g., manually or automatically using control systemsknown in the art) conveyor belt type, or alternative, system, which mayallow filter band 1006 to pass through discrete process zones, which mayinclude but are not limited to, washing, rinsing, and stripping zones.Vacuum filter band 1006 may include one or a plurality of bands, whichmay pass through the process zones. For example, in some embodiments,one vacuum filter band may pass through each individual zone. The rateat which the resin slurry is pumped onto vacuum filter band 1006, aswell as the rate of movement of vacuum filter band 1006 itself may beautomatically or manually altered as necessary.

In some embodiments, spray nozzles 1008A-C may be positioned adjacentvacuum filter band 1006 and configured to distribute water, acids, andother treatment agents. For example, spray nozzle 1008A may bepositioned above vacuum filter band 1006 and may be operativelyconnected to hypochloric (HCL) acid storage chamber 1012. Spray nozzle1008A may be configured to dispense HCL to vacuum filter band 1006.Similarly, spray nozzle 1008B may be operatively connected to NaOHstorage chamber 1014 and may be configured to dispense NaOH to vacuumfilter band 1006. Spray nozzle 1008C may be operatively connected torinse water storage chamber 1016 and may be configured to dispense rinsewater to vacuum filter band 1006. Each spray nozzle may be connected toone or more pumps, which may control the rate of flow out of spraynozzles 1008A-C.

The embodiment shown in FIG. 10 may provide an extremely high level ofoperational flexibility and control over each individual treatmentparameter. For example, the depth of the resin cake may be determined bythe loading speed of the resin slurry onto moving vacuum filter band1006. The treatment and/or exposure time of the resin in a particularprocess zone may be determined by the speed of a particular vacuumfilter band. Further, the extraction volume may be precisely controlledby varying the flow rate of the agents (e.g., water, acids, etc.)sprayed by nozzles 1008A-C onto the resin cake on vacuum filter band1006. Drying of the resin and fluid recovery may be regulated by thelevel of the vacuum (or negative air flow) applied. In addition, thedrying of the resin and the discrete separation of each process zoneprevents any uncontrolled overlapping of each treatment step. Vacuumfilter band 1006 may be operatively connected to a number of collectionchambers 1014A-D.

In some embodiments, collection chambers 1014A-D may be configured toreceive liquids and/or solid material from vacuum filter band 1006. Forexample, each collection chamber may apply a negative pressure to band1006 to assist in dewatering the resin slurry. In some embodiments,system 1000 may include collection chamber 1014A configured to receivewater extracted from the resin slurry and provide that water to rinsewater storage chamber 1016. In some embodiments, rinse water storagechamber 1016 may include a reverse osmosis unit, which may be used tomanage the quality of the polisher stage.

In some embodiments, spray nozzles 1008A-B may be configured to spraydiluted acid, or other metal removing chemicals onto the resin cake inorder to mobilize and remove transition metals trapped on the resin, theresulting acid may be collected in collection chambers 1014B-C as amixed metal regenerant. Collection chambers 1014B-C may provide anyremaining liquids to brine collection tank 1018, which may provide anoutput to the system shown in FIG. 14. Spray nozzle 1008C may beconfigured to reuse the water recovered from collection tank 1014A, theresin may be rinsed to remove any residual acid from the previous zones.The resin may be given a final rinse using fresh water. The watercollected in this zone may then be recycled into one or more of theinitial stages (e.g., ion exchange tank 1002, holding vessel 1004,vacuum filter band 1006) and used to extract, rinse, and fluidize theresin.

Once the resin has received its final rinse, the resin may now bestripped of transition metals, reconditioned in its acid (proton) form,and after undergoing a quality control check, may be ready for reloadinginto front end ion exchange tanks for reuse at the front end site.Several variations of the embodiments described herein may be employedbased upon the characteristics of the resin to be processed.

In some embodiments, after a certain number of reuses, the processwaters used in the initial stages for rinsing and backwashing may besent to an onsite front end system for treatment and continued reuse,for example, system 102, 200, and/or 300. The removal of any tracemetals and/or other contaminants may allow the process water to berecycled and reused repeatedly. This drastic reduction in waterconsumption is a substantial improvement and may significantly reducethe cost of the process.

Alternatively, the front end ion exchange tanks may be stripped andregenerated in a more traditional process. In such a process, the resinsmay be left inside the ion exchange tanks and may be back flushed withwater to remove any trapped particles and solids. This may also fluidizethe resin bed and counter any compaction that may have occurred duringthe loading stage of the front end system. The resins can also beextracted from each individual front end ion exchange tank usingpressurized water and collected in a larger column for processing as abatch. Upon completion of the first stage processing and reconditioning,batch processed resins may be reloaded into individual front end ionexchange tanks for reuse at the front end site.

In some embodiments, after rinsing, acids may then be used to strip thecaptured metals from the ion exchange resins and to recondition theresins to their original proton form. This regeneration procedure mayresult in an acidic, mixed metal solution while the stripped andreconditioned columns are quality checked for proper reconditioning andthen sent back for reuse in the front end system.

Referring again to FIG. 10, in operation, the resin may be removed andrinsed with high velocity water streams from the resin tank and thenconsequently exposed to recycled rinse water and reconditioning acids.The contamination or metal loading levels may be configured to run in agradient situation against the resin stream. This may be achieved byloading the resin after the removal from the tanks onto vacuum bandfilter 1006. Vacuum filter band 1006 may then forward the resin throughvarious spraying zones where the different agents and rinse waters areapplied. In this way, the resources may be utilized as efficient aspossible with great economic benefits to the operation of the plant.

Once the target metals and contaminants have been collected in aconcentrated surge tank, the metal of highest affinity to iminodiaceticion exchange resin may be removed in a multiple (e.g., 4 or 6) columnsetup. Again, the present disclosure may use the selectivity of afunctional group to collect specifically valuable transition metals. Forexample, as copper has the highest affinity in this example, the firstmetal to be removed and purified may be copper sulfate. This may beachieved by a controlled overloading of the first resin tank in thesetup. Overloading the first resin tank may result in a pure orsubstantially pure copper loading in that tank. The following resintanks may be linked in a serial fashion, so that the so called primarycolumn can now move out of the series and undergo the copper sulfateharvesting with diluted sulphuric acid. The formerly secondary columnnow may undergo the same loading process until it has reached a pure orsubstantially pure copper loading. This process is relatively easy tocontrol as the loading time is a simple function of copper concentrationand volume pumped over the resin.

Referring now to FIG. 11, a flowchart 1100 depicting operationsconsistent with stripping and regeneration system 1000 of the presentdisclosure is provided. Flowchart 1100 may include receiving the ionexchange (resin) tanks from front end system (1102). Operations mayfurther include removing the resin from the ion exchange tanks andgenerating a resin/water slurry (1104). Operations may further includeproviding the resin/water slurry to a vacuum filter band having threedistinct zones (1106, 1108, 1110). Resin may move from zone 1, to zone2, to zone 3, and the recovery acid may move in an opposing direction tothe flow of the resin, i.e., zone 3 to zone 2 to zone 1. Operations mayfurther include providing the resin back to the front end system andproviding the metal solution for enrichment (1112), which is discussedin further detail below.

Referring now to FIG. 12, an embodiment of a metal specific purificationsystem 1200 is provided. Here, the mixed metal strip solution, orregenerant, from the system of FIG. 10 may be adjusted and controlled tothe necessary pH levels (if required) and then pumped into a series ofchelating ion exchange resin purification units, as shown in FIG. 12.

In some embodiments, system 1200 may include a plurality (e.g. 4 ormore) of purification units (e.g., resin tanks), which may utilizeselective, chelating ion exchange resin or silical gels. The arrangementmay be designed to achieve continuous flow of the re-conditioningsolution through system 1200. For each target metal, one or moreextractor units may be employed. In the particular embodiment depictedin FIG. 12, three or more purification units are loaded with thereconditioning solution in series. This results in primary purificationunit 1202, secondary purification unit 1204, and tertiary purificationunit 1206. Other configurations and numbers of tanks are also within thescope of the present disclosure. In addition to trapping and retaining apreferred metal in each purification unit or resin tank, system 1200 mayalso successfully purify and isolate a particular target metal. Theenriched and purified target metal, as it is absorbed on the resin inthe purification units, may then be harvested as described below withreference to FIGS. 13-14.

In operation, once a purification unit goes offline, the previouslysecondary purification unit may be switched into the flow path as theprimary purification unit. Being already enriched partly, it mayexperience oversaturation quickly and purify the trapped metalaccordingly. This may be an ongoing process where the purification unitsare switched into the flow path upstream. This may allow for theoperation of a limited number of purification units continuously.

Table 1, provided below, depicts one particular embodiment of theoperation of metal purification system 1200 of FIG. 12. Once primarypurification tank 1202 has been supersaturated, the vessel may be rinsedor blown empty and switched to regeneration mode. The former secondarypurification tank 1204 may now be switched into the primary position andthe former tertiary tank 1206 may now go into the secondary position andthe regenerated tank 1208 may now switch into the tertiary position. Thesupersaturation may ensure the displacement of lower affinity metals(depending upon mixed metals composition and ion-exchange ligand) by thehighest affinity metal. In this way, purities of approximately 99% ofthe target metal may be achieved (e.g., S930, TP207, SIR-1000).

TABLE 1 Primary Secondary Tertiary Regeneration 1 A B C D 2 D A B C 3 CD A B 4 B C D A 5 A B C D

In some embodiments, purification units 1202, 1204, 1206, 1208 may eachcontain selective ion exchange resins and the units may be arranged inthe rotating configuration described in Table 1. This system may beconfigured to selectively target and capture an individual metal byusing supersaturation to leverage the inherent relative affinity of theresin to different metals.

In some embodiments, during supersaturation, regenerant may becontinually introduced into first purification unit 1202 even after theeffective capacity of the resin has been exhausted. As the target metalof a particular purification unit may have a higher affinity to theresin, relative to the other metals in the solution, continued exposureof the resin to the regenerant may cause the higher affinity targetmetal ions to dislodge and replace other non target metals which mayhave been captured on the resin. After a designated volume ofsupersaturation, the resin of a particular purification unit may containonly the metal targeted by that module. Some or all other metals nottargeted by that purification unit may remain in the regenerant solutionand continue to the next purification unit, where the same process thentargets and captures another metal. Depending on the number of metals inthe regenerant from the front end resin tanks, a corresponding number ofpurification units each targeting a specific metal may be arranged inseries such that all the metals may be separated. In this manner, theindividual metals of a mixed metal regenerant may be identified,targeted, separated by capture on the resin, and purified.

It should be noted that the ability to separate individual metalfractions from a multi-metal regenerant represents a drastic improvementover existing ion exchange processes as purified metals can be directlymanufactured into end products. Currently, processes involving mixedmetal solutions require additional and costly processing before usableproducts can be recovered.

In some embodiments, the regenerant from FIG. 12 may now be cleansed ofmetals and may effectively be an acid again, albeit at lower strengthand concentration, and with trace contaminants. The ion exchange processof FIG. 12, in which metals in the regenerant are exchanged for protonson the resin, also has the additional effect of regenerating theregenerant (acid) itself by the addition of free H+ ions (from the ionexchange resin). Upon exiting system 1200, the regenerant may be infusedwith a small volume of fresh, highly concentrated acid in order torestore its strength and concentration to near original levels. In thismanner, the regenerant can then be recycled back into other systems(e.g., system 1000) several times and used to strip and reconditionincoming front end columns. The ability to repeatedly reuse acid in thisfashion is a significant improvement over existing ion exchangeprocesses; in which acid consumption constitutes a large percentage ofoperating costs and the need to discard large amounts of waste acidcreates a liability.

In some embodiments, once a primary purification unit (e.g. primarypurification unit 1202 in FIG. 12) has reached supersaturation and isfully loaded with a target metal, it may be taken offline and readiedfor stripping and regeneration. The purification unit may be backflushed with water to remove any interstitial fluid, residual loadingsolution, solids and impurities, as well as to fluidize the resin bedand to counter any compaction. The process waters from this stage mayalso be sent to an onsite or offsite front end system for treatment andrecycling. The repeated reuse of this process water may constitute asignificant decrease in water consumption and operating costs whencompared to existing ion exchange processes.

Referring now to FIGS. 13-14, embodiments depicting a repetitivestripping system 1300 are provided. As discussed above, the ion exchangetanks from the front end system may be stripped with vacuum filter band1006 associated with system 1000. In contrast, the metal filledpurification units from FIG. 12 may be stripped using repetitivestripping system 1300. System 1300 may utilize a repetitive strippingprotocol regulated by an automated concentrate management system basedon a programmable logic controller.

In some embodiments, system 1300 may include a series of acid tanks, forexample, acid tank A 1302, acid tank B 1304, and acid tank C 1306. Afully loaded purification tank or column 1310 may be provided fromsystem 1200 shown in FIG. 12. Fully loaded column 1310 may receiveadditional acid from make-up strip acid tank 1312 and may provide anoutput to product surge tank 1308. In one possible sequence, acid tank A1302 may be pumped through fully loaded column 1310, feeding into tank1308 (final product, product surge tank) (step 1). Acid tank B 1304 maythen be pumped through column 1310 (step 2), followed by acid tank C1306 being pumped through column 1310 (step 3). Fresh diluted acid maythen be pumped through column 1310 (step 4). After the acid treatmentloaded column 1310 may undergo rinsing with water for completeregeneration. Step 1 may empty into product surge tank 1308, step 2 mayempty into acid tank A 1302, step 3 may empty into acid tank B 1304, andstep 4 may empty into acid tank C 1306.

In some embodiments, each batch of acid may be used to strip severaldifferent purification units and each purification unit may be strippedby a series of acid batches of decreasing metal and increasing freeproton concentration. Consequently, the first batch of acid to beintroduced into a saturated purification unit (e.g. column 1310) may bethat which has already been used the most times relative to the otherbatches within a set of acid batches. Upon exiting the purificationunit, this acid batch may have its maximum metal and minimum free protonconcentrations respectively. At that point, the acid batch may beremoved from stripping system 1300 and sent for final processing intoend products.

In some embodiments, the stripping process may continue in this fashionwith each subsequent acid batch having been used one fewer time than thebatch preceding it. Other than the first batch, which may be sent to forfinal processing into end products, all other batches may be stored foruse with the next saturated column. The final batch of acid may be freshacid, to insure that the resin is adequately stripped of metals andproperly regenerated and reconditioned for reuse. For example, referringagain to FIG. 13, in a four batch set of acids, consisting of a threestrip batch in acid tank 1302, a two strip batch in acid tank 1304, aone strip batch in acid tank 1306, and a fresh acid batch in tank 1312,the three strip batch may be used first, and then sent for finalprocessing into end products as shown in FIG. 15. Then, the two stripbatch may be used, which may become the three strip batch for the nextcolumn. The one strip batch may then be used, and may then become thetwo strip batch for the next column. Finally, the fresh acid may be usedand may become the one strip batch for the next column.

In some embodiments, this stripping protocol may markedly decreasechemical consumption by maximizing the utilization of free acid. Thismay provide a substantial advantage over existing ion exchange processesthat may generate large volumes of waste acids requiring additionaltreatment and disposal. As a result, less acid may be consumed, whichmay constitute a significant operational cost.

In some embodiments, the high purity and concentration of the metal mayallow for the regenerant to be directly and economically processed intoa metal salt chemical end product, with little or no byproducts orwastes. In this manner, the columns or resin tanks may be stripped andregenerated for reuse and the target metal may be rendered as a highpurity, highly concentrated metal salt solution. This process may be asignificant improvement over existing ion exchange processes in that theacid may not be consumed and discarded as a waste, but rather becomes aningredient of a commercially salable end product. This may result insubstantially lower operating costs, as well as in eliminating thecostly requirement for handling and disposing of waste acids.

Referring now to FIG. 14, an exemplary embodiment of a system 1400incorporating some or all of systems 1200 and 1300 is provided. System1400 may include purification units 1402, 1404, 1406, and 1408, whichmay be configured similarly to those described above with reference toFIG. 12. System 1400 may further include acid tanks 1410, 1412, 1414,and 1416, which may be configured similarly to those described abovewith reference to FIG. 13. Alternative arrangements of purificationunits and acid tanks are also within the scope of the presentdisclosure.

In some embodiments, system 1400 may be used to recover metal sulfatesfrom iminodiacetic ion exchange resins by utilizing a repetitivestripping system such as that described above with reference to FIG. 13.The application of a concentration gradient in the stripping acid mayallow for an efficient utilization of the provided protons as well as inminimizing rinse water requirements and complex process controlling.

In some embodiments, system 1400 may be used to apply the acid used torecover the pure metal ions from the ion exchange resin in a multipleand repetitive fashion. Further, it always follows with an exposure ofless used acid, which means the reconditioning and cleaning may becomemore and more efficient in the ongoing process. In addition, residualfree protons may be minimized in the final, highly concentrated metalsulfate solution. This feeds perfectly into the crystallization process(discussed in FIG. 15) following the metal sulfate recovery as thesolubility is significantly decreased in the increased pH environment.

In some embodiments, the multiple acid exposure via tanks 1410, 1412,1414, and 1416 also simplifies the rinsing of the resin after the acidtreatment. In this way, less copper (or other metals) may be leftremaining on the resin. As a result, issues regarding when to cut therecovery fraction and to switch to rinsing may be eliminated. Intraditional column reconditioning approaches, the metal concentration inthe effluent may be slowly increasing to a maximum (desired)concentration and then decreasing during the ongoing. All this solutionmay be typically collected into one tank. This introduces a dilatuioneffect which may be counterproductive to receiving highest metalrecovery concentrations (i.e. 100-150 g metal salt per liter). In thedescribed, repetitive exposure of the same saturated column topre-defined, pre-concentrated recovery solutions, these lowconcentration fronts and tails of the column wash may be avoided andovercome. The last column exposure to fresh diluted acid provides aperfect scenario to rinse the column acid free with fresh or recycledrinse water before it switches back into the enrichment train. Thissimplification makes the recovery process order more efficient.

In some embodiments, while the columns in the core process may beconnected in series, the first column (e.g., purification unit 1402) inline (or the primary columns) may be supersaturated with copper ions.The copper ions, in this particular example, may remove all loweraffinity metal ions.

In operation, the primary column may then be taken out of the systemonce all ion exchange sites have been occupied by the target metal, forexample, the copper ions discussed above. The primary column may nowmove into the concentrate manager section of system 1400, namely, acidtanks 1410, 1412, 1414, and 1416. Here, acid solution which has alreadybeen exposed to two primary columns may be pumped first over the columnto receive a highly enriched, low remaining free proton solutionindicated by acid tank 1416, i.e., strip D. The column may then betreated with further acid rinses from acid tank 1412 (i.e., strip B) andacid tank 1414 (i.e., strip A) until fresh acid solution is pumped overthe column. All of the copper may now be removed and the primary columnmay undergo a brief water rinse. The column may then ready to returninto the loading cycle.

In some embodiments, system 1400 may be configured to utilize theprotons delivered by the acid as effectively as possible. System 1400may also remove the necessity to manage the eluting high concentrationpeak from the column in the metal recovery process. The overall recoveryprocess therefore provides a more robust and simplified approachproviding a much better, higher concentrated and less acidic feedsolution for the metal salt crystallization.

Referring now to FIG. 15, a system 1500 configured to process commercialmetal salts is provided. At system 1500 the metal salt concentrates fromsystem 1400 may be processed into commercial quality metal salts usingprocesses, which may include, but are not limited to, vacuumevaporation, crystallization, and spray drying. The techniques employedmay depend upon the desired characteristics and specifications for theproduct. The high purity and concentration of the concentrate may allowfor very economical production of a wide range of specificationsdepending on customer demand. After undergoing quality checks, the endproduct may be packaged and shipped to customers or other distributionnetworks.

In some embodiments, system 1500 may include receiving vessel 1502,which may be configured to receive and/or store the output from system1400. The metal solution may be transferred from receiving vessel 1502to evaporating chamber 1504. Water removed from evaporating chamber 1504may be redistributed to any of the other systems of the presentdisclosure. The output from evaporating chamber 1504 may be provided tocrystallizer 1506, which may be operatively connected to cooling machine1508.

In some embodiments, the metal sulfates are recovered in the centralprocessing units as high concentration metal sulfate solutions.Crystallizer 1506 may utilize various crystallization techniques torecover the metal sulfates as solid products. This may be achieved bycooling the highly concentrated metal sulfates, which may reduce thesolubility to a level where the solid metal sulfates start tocrystallize. The resulting crystallized metal sulfates may be depositedin final crystallization tank 1510. The crystallized metal sulfates maythen be sent to electrowinning chamber 1510. Electrowinning chamber 1510may involve various processes used to extract the target metals. Itshould be noted the systems of the present disclosure may be used toproduce metal salts, which may be far more lucrative than producingmetallic or elemental products. For example, metal sulfates, like copperpenta hydro sulfate, may be fed directly back into printed circuit boardmanufacturing, plating, chip manufacturing and many other processes. Forcopper sulfate, the recovered mass as sulfate may be approximately fourtimes more than the pure metal. It should be noted that although FIG. 15primarily depicts copper as the metal, the systems of the presentdisclosure may work with any number of metals. Some other metalsinclude, but are not limited to, nickel, zinc, etc.

In some embodiments, the processes of the central processing facilitymay be monitored by sensors and computers linked into a central databasesoftware system, which may continually record all of the operatingparameters, criteria, performance, and results in real time. Togetherwith data from the front end column RFID tags, this data may beevaluated by database mining software to identify trends and optimumoperating parameters for the various categories of front end columnsarriving at the central processing facility. The same or similarsoftware may also analyze operating parameters of the processes of thecentral processing facility. As the database accumulates informationover time, it may be able to recommend optimized operating parametersfor front end column sorting and regeneration, target metal moduleloading and stripping parameters, and overall process efficiency;further reducing costs and chemical consumption.

As discussed above, embodiments of the present disclosure may utilize anRFID tracking and management system. For example, and referring again toFIG. 3, individual ion exchange tanks 302A-G may be tracked and managedusing a networked RFID (Radio Frequency Identification) system. Each ionexchange tank may be fitted with a unique RFID tag capable of recordingand storing at least one characteristic associated with the tank. Forthe purposes of this disclosure the term “characteristic” may refer tothe physical, chemical and historical characteristics of a particularion exchange tank. A network of handheld, truck mounted, and factorybased RFID readers may connect wirelessly into an asset managementsoftware system, which may be located at the central facility orelsewhere, and mirrored at corporate headquarters. This system may allowfor the real time, simultaneous tracking of thousands of ion exchangetanks through every stage of the service process. This may result inmaximized efficiencies for tasks such as ion exchange transportation,exchange scheduling, management of resin degradation, and categorizationof like ion exchange tanks for batch stripping and regeneration. Costsavings may also be realized from the prevention of operational errorsassociated with incorrect column/resin identification. This historicaldatabase may be updated in real time and may operate in conjunction witha fuzzy logic based process optimization software system to continuouslyimprove operational efficiencies.

In some embodiments, at the core process central facility for example,operational parameters such as reagent selection and dosing, resin batchcomposition, stripping efficiencies, and product quality may be loggedand managed by a fuzzy logic based software system. This information,along with data collected from the RFID Management System may beincorporated into a unified database containing a detailed historicalaccounting of every operational parameter of the service process. Thefuzzy logic system may continuously mine this database to identifyoptimally efficient parameters and present suggested process parametersto technicians. The system may “learn” from each ion exchange tankprocessed such that as the database grows over time, it may identify themost efficient set of parameters to process any given ion exchange tankor set of tanks. Consequently, when a truck carrying saturated ionexchange tanks enters the central facility, and before the driver haseven turned off the engine, the system will know exactly what ionexchange tanks have arrived, which client each ion exchange tank isfrom, how long the ion exchange tank was in service operation, and howthey should be sorted. From the database, the system may review thehistorical data for each ion exchange tank, including such variables asrelative metal concentrations and stripping reagents. Comparing theresults from each previous set of parameters, the software may thenidentify the optimal set for the most efficient and cost effectiveprocessing of the ion exchange tank. The system may also apply the sameprocesses to refining core process and product production operatingparameters. The data and optimized process parameters may minimize thelearning curve for new central facilities, as well as internationalexpansion.

In some embodiments, the teachings of the present disclosure may be wellsuited to process the rinsewaters of the electroplating and surfacefinishing industries. The principal objective of electroplating may beto deposit a layer of a metal possessing a desired property, such asaesthetic appearance, hardness, electrical conductivity, or corrosionresistance, onto the surface of a material which lacks such properties.Typically the material being plated may be another metal, such as steelor zinc; though other materials such as plastic may also be plated.Parts which are plated may range from common items such as bolts, nails,buttons, and zippers, and industrial items such as engine components,turbine blades, hydraulic pistons, and aerospace components, to hightech items such as integrated circuits, data discs, and copper cladlaminates used in printed circuit boards.

Electroplating, technically a process known as electrodeposition, may beachieved by turning the part to be plated into a cathode by running anegative charge through it, and then immersing that part in anelectrolyte (or plating bath) composed of dissolved metal salts such asCuSO4; the metal to be plated effectively becomes the anode. Insolution, the dissolved metals may exist in ionic form with a positivecharge and are therefore attracted to the negatively charged parts. Whena direct current, usually supplied by a rectifier, flows though thecircuit, the metallic ions are reduced at the cathode (part) and plateout. As the process continues, the composition of the plating bath maychange as metals are removed from solution. Consequently, baths must bemaintained with the addition of supplemental ingredients. While somebaths may be maintained indefinitely, others (especially where precisionis required) must be periodically dumped and replaced with a fresh bath;the discharge of spent plating baths is a major source of wastewater.This may not be accessible to this process without extensive bathdilution prior to processing.

Once plating has reached the desired thickness, the parts may be removedfrom the plating bath and may proceed through a series of rinsing tanksin a counter-flow arrangement. Fresh water may be supplied from thefinal tank, and fouled rinsewater from the first tank may be continuallydischarged. Thorough rinsing may be essential as any residual platingsolutions may result in clouding, blemishes or other surfaceirregularities; resulting often in the use and discharge of largevolumes of water. As the parts leave the plating bath, they “drag out”the plating solution still adhered to their surfaces. This dragout isone of the primary reasons why rinsewaters are so heavily contaminatedby heavy metals.

In some embodiments, to process these electroplating rinsewaters andspent plating baths, a front end system may be installed on sitecontaining a suitable volume of ion exchange resin (housed in columns ortanks) relative to the daily volume of rinsewaters and concentration ofmetals. Each process step may treat or remove contaminants within thewastewater, with the metals being captured in the columns.

In some embodiments, upon exiting the front end system, the treatedwater could then be directly recycled into the rinsing process. If thewater quality requirement of the electroplating process so requires, thetreated water could be further processed with a reverse osmosis ortraditional demineralization system prior to reintroduction into therinsing process. The saturated front end columns may be replaced withfreshly reconditioned columns, and then sent to a central processingfacility for stripping and reconditioning. The extracted metals may thenundergo the separation and purification process (as described above),and then be processed into commercially salable end products.Embodiments of the present disclosure may confer the benefits of onsitewastewater recycling, as well as reclamation of metals, at a cost lowerthan currently available alternatives.

Embodiments of the present disclosure may utilize a multi-stage processto collect, transport, and treat wastewater having various metals. Morespecifically, this disclosure refers to an ion exchange based wastewatertreatment and recycling system for the treatment of metal bearingwastewater, comprised of an independent front end unit located at thesite of the wastewater generation, and a central processing facilitywhere components of the front end module are collected and processed.After treatment, wastewater exiting the invention may be suitable forrecycling or legal discharge, while metals are collected, separated,purified and processed into end products. As economic, regulatory, orother considerations so require, the central processing facility mayalso be located on the same site as the front end system.

In stage one, metals may be stripped from the resins and the resinsregenerated to their original proton form by an innovative conveyer beltvacuum filter band unit (as shown in FIG. 10); which may utilize acascading setup to minimize rinsewater consumption and enhance controlover operational parameters. After extraction from their individualcolumns or ion exchange tanks, resin may be spread onto a filter bandwhich travels through a number of zones, each with a discrete processstep (e.g., rinsing, stripping, and reconditioning). After undergoingstage one processing, resins may be reconditioned to their originalproton form and ready for reuse in front end units, while the metals maybe stripped into a solution for further processing in stage two.

In stage two, the mixed metal strip solution, or regenerant, from stageone may be pumped into a series of chelating ion exchange resinpurification units; each consisting of a number of columns or tanks,arranged in a merry go round configuration, and loaded with selectiveion exchange resins. Each purification unit may selectively target andcapture an individual metal by using supersaturation to leverage theinherent relative affinity of the resin to different metals. Byarranging a number of purification units in series, individual metalfractions may be extracted from the mixed metal regenerant.

Once a column in a particular purification unit reaches supersaturation,it may then be taken offline, stripped of the metal, and regeneratedusing an innovative repetitive stripping process controlled by anautomated concentrate manager as shown in FIGS. 12-14. In this process,each batch of acid may be used to strip several different columns andeach column may be stripped by a series of acid batches of decreasingmetal and increasing free proton concentration. This may result inmarkedly decreased chemical consumption and a strip solution of highconcentration and purity. The high purity and concentration of the metalmay allow for the regenerant from stage two to be directly andeconomically processed into a metal salt chemical end product. In stagethree, the stage two single metal regenerant may be processed directlyinto commercially salable end products using processes such as vacuumevaporation, crystallization, and spray drying as shown in FIG. 15.

Some of the embodiments (e.g., those associated with the RFID trackingand management system) described above may be implemented in a computerprogram product that may be stored on a storage medium havinginstructions that when executed by a processor perform the messagingprocess described herein. The storage medium may include, but is notlimited to, any type of disk including floppy disks, optical disks,compact disk read-only memories (CD-ROMs), compact disk rewritables(CD-RWs), and magneto-optical disks, semiconductor devices such asread-only memories (ROMs), random access memories (RAMs) such as dynamicand static RAMs, erasable programmable read-only memories (EPROMs),electrically erasable programmable read-only memories (EEPROMs), flashmemories, magnetic or optical cards, or any type of media suitable forstoring electronic instructions. Other embodiments may be implemented assoftware modules executed by a programmable control device.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the invention. Asused herein, the singular forms “a”, “an” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that the terms “comprises”and/or “comprising,” when used in this specification, specify thepresence of stated features, integers, steps, operations, elements,and/or components, but do not preclude the presence or addition of oneor more other features, integers, steps, operations, elements,components, and/or groups thereof.

It should be noted that any dimensions, sizes, lengths, dosing amounts,densities, flow rates, dosing agents, etc, are merely provided forexemplary purposes and are not intended to limit the scope of thepresent disclosure. For example, any dimensions or sizes listed on anyof the Figures are merely provided as an example, as these sizes may bevaried by persons of ordinary skill in the art.

A number of implementations have been described. Nevertheless, it willbe understood that various modifications may be made. Accordingly, otherimplementations are within the scope of the following claims.

1. A wastewater treatment system comprising: a front end systemincluding at least one resin tank configured to contain an ion exchangeresin configured to target a particular metal, the at least one resintank configured to receive an output from an oxidation reactorconfigured to receive a flow of wastewater from a wastewater producingprocess; and a central processing system configured to receive asaturated resin tank from the at least one resin tank, the centralprocessing system including a vacuum filter band system configured toreceive a slurry from the saturated resin tank and to provide acascading resin rinse to the slurry, the central processing systemfurther including a repetitive stripping system configured to receive ametal-filled purification unit from a metal specific purificationsystem, the repetitive stripping system further configured tosequentially apply the contents of a plurality of acid tanks to themetal-filled purification unit to generate a metal salt.
 2. Thewastewater treatment system of claim 1, wherein the at least one resintank includes a plurality of resin tanks arranged in a seriesconfiguration.
 3. The wastewater treatment system of claim 1, whereinthe ion exchange resin is an iminodiacetic resin.
 4. The wastewatertreatment system of claim 3, wherein the iminodiacetic resin is in aproton form.
 5. The wastewater treatment system of claim 1, wherein themetal specific purification system is configured to receive a metalsolution from the vacuum filter band system, the metal specificpurification system including a plurality of purification units, themetal-filled purification unit generated by allowing the metal solutionto flow through the plurality of purification units.
 6. The wastewatertreatment system of claim 1, wherein each of the plurality of acid tanksincludes a different acid concentration.
 7. The wastewater treatmentsystem of claim 1, wherein the vacuum filter band system includes aplurality of spraying zones, each of the plurality of spraying zonesconfigured to apply a solution to the slurry and to substantiallydewater the slurry by applying a negative pressure to the vacuum filterband.
 8. The wastewater treatment system of claim 1, wherein theoxidation reactor further includes a reaction coil configured topressurize at least a portion of the oxidation reactor.
 9. Thewastewater treatment system of claim 1, wherein the at least one resintank includes one or more radio frequency identification (RFID) tagsconfigured to record at least one characteristic associated with the atleast one resin tank.
 10. The wastewater treatment system of claim 1,wherein the metal salt is transferred to a metal salt processing systemfor cooling and crystallization.
 11. A method for treating wastewatercomprising: providing a front end system including at least one resintank having an ion exchange resin configured to target a particularmetal, receiving, at the at least one resin tank, an output from anoxidation reactor configured to receive a flow of wastewater from awastewater producing process; receiving, at a central processing system,a saturated resin tank from the at least one resin tank; receiving aslurry from the saturated resin tank at a vacuum filter band system;providing a cascading resin rinse to the slurry at the vacuum filterband system; receiving, at a repetitive stripping system, a metal-filledpurification unit from a metal specific purification system; andsequentially applying, at the repetitive stripping system, the contentsof a plurality of acid tanks to the metal-filled purification unit togenerate a metal salt.
 12. The method of claim 11, wherein the at leastone resin tank includes a plurality of resin tanks arranged in a seriesconfiguration.
 13. The method of claim 11, wherein the ion exchangeresin is an iminodiacetic resin.
 14. The method of claim 11, wherein theiminodiacetic resin is in a proton form.
 15. The method of claim 11,further comprising receiving a metal solution from the vacuum filterband system at the metal specific purification system, the metalspecific purification system having a plurality of purification units,and generating the metal-filled purification unit by allowing the metalsolution to flow through the plurality of purification units.
 16. Themethod of claim 11, wherein each of the plurality of acid tanks includesa different acid concentration.
 17. The method of claim 11, furthercomprising providing a plurality of spraying zones at the vacuum filterband system, each of the plurality of spraying zones configured to applya solution to the slurry and to substantially dewater the slurry byapplying a negative pressure to the vacuum filter band.
 18. The methodof claim 11, further comprising providing a reaction coil within theoxidation reactor configured to pressurize at least a portion of theoxidation reactor.
 19. The method of claim 11, further comprisingrecording at least one characteristic associated with the at least oneresin tank via one or more radio frequency identification (RFID) tags.20. The method of claim 11, further comprising cooling the metal salt ata metal salt processing system.